There has been known a motor rotor used in sealed rotary compressors such as scroll compressors (see, for example, Patent Documents 1 and 2). FIG. 7 is a top view of a conventional 6-pole motor rotor. As illustrated in FIG. 7, a rotor 1 is provided with four elongated refrigerant gas holes 3 and two positioning holes 4 around a shaft hole 2. There are also provided six rivet holes 5 on the outside in the radial direction of the rotor 1. The positioning holes 4 double as refrigerant gas holes 3.
Passing through the rivet holes 5 are rivets that fix components of the rotor 1 including a rotor core (a rotor laminated steel plate), an end plate 6, a magnet (a permanent magnet), a balance weight 7, and an oil separation plate. The refrigerant gas holes 3 are through holes each forming a path of refrigerant gas to improve the oil separation efficiency. In the process of magnetization of the rotor 1, positioning pins are inserted into the positioning holes 4 to set the rotation position of the rotor 1 to a predetermined position.
In the manufacturing process of a rotary compressor, the rotor is magnetized after being fixed to the shaft extending from the compression unit in the casing by shrink fitting. In the magnetization of the rotor, the rotor and a magnetizer each need to be set at a predetermined position in the rotation direction, and thus positioning pins are inserted into the positioning holes of the rotor to set the position of the rotor in the rotation direction at a predetermined position. In this case, since the rotor is fixed to the shaft extending from the compression unit by shrink fitting, the positioning pins are inserted into the rotor through the positioning holes located on the rotor end surface on the opposite side of the compression unit distant from the compression unit. During the magnetization, a magnetic force is exerted to rotate the rotor. Accordingly, the positioning pins also prevent the rotation of the rotor at the time of positioning.
Patent Document 1: Japanese Patent Application Laid-open No. 2005-143299
Patent Document 2: Japanese Patent Application Laid-open No. 2008-14320